Highchairs for infants and children typically include a seat supported above the floor and a tray attached to the seat upon which food and drink for the child can be placed. Oftentimes, the tray is removable from the seat for easy cleaning. Additionally, the tray can be adjusted with respect to the seat. These tray adjustment mechanisms, however, can be improved to be more intuitive and user friendly. Also, the height of the seat with respect to the ground can also be adjusted. These seat-height adjustment mechanisms can also be improved to be more intuitive and user friendly.